This invention relates to valves and has particular relevance to diffuser valves used to desseminate material within a hopper or the like, although as will be appreciated from the ensuing description the present invention has wide application and may be put to a number of uses.
When particulate materials such as powders are stored in a hopper problems often arise because the powder tends to "bridge" or, even in some cases pack solid, and this may be the case whether the material inside the hopper is moist or dry. When material within a hopper does bridge or pack solid if there are no mechanical facilities for correcting the condition it is necessary for the materials to be loosened manually so that predetermined flows from the hopper can be maintained.
To overcome the problem of bridging or packing it is known to provide a plurality of nozzles which are provided in strategic positions on or within a hopper and to apply high pressure air via the nozzles to the material within the hopper in an endeavour to correct the problem. Other means for overcoming the problem have included dispersing air through members which protrude into the hopper interiors however neither of the solutions to the problem have proved to be totally effective or economic.